High speed, low cost marking of packages of various kinds is desirable in many applications. For instance, in the manufacture of semiconductor devices each part must be marked with a part number and is typically marked with a manufacturer's identifier. These markings are required to be resistant to corrosion and abrasion. In addition, the degree of handling required to produce the marking must be reduced to as great a degree as possible. This is of particular concern where the parts are to be marked subsequent to testing, so that only qualified parts will be marked.
The most common prior method of marking the metal surfaces of semiconductor packages utilizes ink. Tested parts are separated by lot and marked utilizing a stencil, or other process, with a wet ink. This ink must then be cured for a period of time. Not only does this process involve several stages of handling, but the resulting mark may be removed by abrasion.
More recently, the use of laser energy which exposes the surface to be marked through a mask has been used in the marking of semiconductor packages and similar articles. Typically, an ink which is ablated by the laser energy is applied. Other means of laser marking have also been implemented. However, there still exists a need for a very low cost laser marking method which produces a high quality, abrasion resistant mark at as low a cost as possible.